# \[IGN-5581\]PyDataset over received from sendRequest behaves differently

**URL:** <https://forum.inductiveautomation.com/t/ign-5581-pydataset-over-received-from-sendrequest-behaves-differently/56278>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [February 17, 2022, 8:06pm UTC](https://forum.inductiveautomation.com/t/ign-5581-pydataset-over-received-from-sendrequest-behaves-differently/56278 "2022-02-17T20:06:43Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![zacht](https://avatars.discourse-cdn.com/v4/letter/z/ea5d25/32.png) [@zacht](https://forum.inductiveautomation.com/u/zacht)\
**Post date:** [February 17, 2022, 8:06pm UTC](https://forum.inductiveautomation.com/t/ign-5581-pydataset-over-received-from-sendrequest-behaves-differently/56278/1 "2022-02-17T20:06:43Z")

</div>

I have setup this test to demonstrate an odd behavior I ran into today. Can anyone help explain what’s happening?

I have two buttons: local and gateway that have the following scripts on their respective actionPerformed event.

![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/3/e37f1d18a05926bd724b6f35057a3b9beaace2b1.png)

```auto
# Local Button
data = system.db.runPrepQuery('Select 1 WHERE 1=?',[1],'Ignition_Data')
print("# Local Return")
print data
print type(data)
print dir(data)
print data[0][0]

```

```auto
# Gateway Button
data = system.util.sendRequest(
	system.project.getProjectName(),
	'queryTest',
	{}
)
print('# gateway return')
print data
print type(data)
print dir(data)
print data[0][0]

```

The message handler has the following script:

```auto
	_l = system.util.getLogger('Query Test')
	_l.info('Message handler called successfully!')
	return system.db.runPrepQuery('Select 1 WHERE 1=?',[1],'Ignition_Data')

```

When I push ‘local’ I get this in the diagnostics window:

```auto
# Local Return
<PyDataset rows:1 cols:1>
<type 'com.inductiveautomation.ignition.common.script.builtin.DatasetUtilities$PyDataSet'>
[' __add__', ' __class__', ' __delattr__', ' __delitem__', ' __delslice__', ' __doc__', ' __ensure_finalizer__', ' __eq__', ' __finditem__', ' __format__', ' __ge__', ' __getattribute__', ' __getitem__', ' __getslice__', ' __gt__', ' __hash__', ' __init__', ' __iter__', ' __le__', ' __len__', ' __lt__', ' __ne__', ' __new__', ' __nonzero__', ' __reduce__', ' __reduce_ex__', ' __repr__', ' __rmul__', ' __setattr__', ' __setitem__', ' __setslice__', ' __str__', ' __subclasshook__', 'binarySearch', 'columnCount', 'columnNames', 'columnTypes', 'data', 'getColumnAsList', 'getColumnCount', 'getColumnIndex', 'getColumnName', 'getColumnNames', 'getColumnType', 'getColumnTypes', 'getPrimitiveValueAt', 'getQualityAt', 'getRowCount', 'getUnderlyingDataset', 'getValueAt', 'hasQualityData', 'isSequenceType', 'rowCount', 'sequenceType', 'setData', 'toString', 'underlyingDataset']
1

```

When I push ‘global’ I get this:

```auto
# gateway return
<PyDataset rows:1 cols:1>
<type 'com.inductiveautomation.ignition.common.script.builtin.DatasetUtilities$PyDataSet'>
[' __add__', ' __class__', ' __delattr__', ' __delitem__', ' __delslice__', ' __doc__', ' __ensure_finalizer__', ' __eq__', ' __finditem__', ' __format__', ' __ge__', ' __getattribute__', ' __getitem__', ' __getslice__', ' __gt__', ' __hash__', ' __init__', ' __iter__', ' __le__', ' __len__', ' __lt__', ' __ne__', ' __new__', ' __nonzero__', ' __reduce__', ' __reduce_ex__', ' __repr__', ' __rmul__', ' __setattr__', ' __setitem__', ' __setslice__', ' __str__', ' __subclasshook__', 'binarySearch', 'columnCount', 'columnNames', 'columnTypes', 'data', 'getColumnAsList', 'getColumnCount', 'getColumnIndex', 'getColumnName', 'getColumnNames', 'getColumnType', 'getColumnTypes', 'getPrimitiveValueAt', 'getQualityAt', 'getRowCount', 'getUnderlyingDataset', 'getValueAt', 'hasQualityData', 'isSequenceType', 'rowCount', 'sequenceType', 'setData', 'toString', 'underlyingDataset']
12:10:30.279 [AWT-EventQueue-0] ERROR com.inductiveautomation.ignition.client.util.gui.ErrorUtil - <HTML>Error executing script for event:&nbsp;<code><b>actionPerformed</b></code><BR>on component:&nbsp;<code><b>Button 1</b></code>.
com.inductiveautomation.ignition.common.script.JythonExecException: Traceback (most recent call last):
  File "<event:actionPerformed>", line 11, in <module>
java.lang.NullPointerException
	at com.inductiveautomation.ignition.common.script.builtin.DatasetUtilities$PyDataSet.pyget(DatasetUtilities.java:123)
	at org.python.core.PySequence$DefaultIndexDelegate.getItem(PySequence.java:532)
	at org.python.core.SequenceIndexDelegate.checkIdxAndFindItem(SequenceIndexDelegate.java:88)
	at org.python.core.SequenceIndexDelegate.checkIdxAndFindItem(SequenceIndexDelegate.java:70)
	at org.python.core.SequenceIndexDelegate.checkIdxAndGetItem(SequenceIndexDelegate.java:61)
	at org.python.core.PySequence.seq ___getitem__ (PySequence.java:377)
	at org.python.core.PySequence. __getitem__ (PySequence.java:373)
	at org.python.pycode._pyx6.f$0(<event:actionPerformed>:11)
	at org.python.pycode._pyx6.call_function(<event:actionPerformed>)
	at org.python.core.PyTableCode.call(PyTableCode.java:171)
	at org.python.core.PyCode.call(PyCode.java:18)
	at org.python.core.Py.runCode(Py.java:1614)
	at com.inductiveautomation.ignition.common.script.ScriptManager.runCode(ScriptManager.java:799)
	at com.inductiveautomation.factorypmi.application.binding.action.ActionAdapter.runActions(ActionAdapter.java:206)
	at com.inductiveautomation.factorypmi.application.binding.action.ActionAdapter.invoke(ActionAdapter.java:297)
	at com.inductiveautomation.factorypmi.application.binding.action.RelayInvocationHandler.invoke(RelayInvocationHandler.java:57)
	at com.sun.proxy.$Proxy40.actionPerformed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
	at java.desktop/java.awt.Component.processMouseEvent(Unknown Source)
	at java.desktop/javax.swing.JComponent.processMouseEvent(Unknown Source)
	at java.desktop/java.awt.Component.processEvent(Unknown Source)
	at java.desktop/java.awt.Container.processEvent(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)
java.lang.NullPointerException: java.lang.NullPointerException

	at org.python.core.Py.JavaError(Py.java:552)
	at org.python.core.PyTableCode.call(PyTableCode.java:180)
	at org.python.core.PyCode.call(PyCode.java:18)
	at org.python.core.Py.runCode(Py.java:1614)
	at com.inductiveautomation.ignition.common.script.ScriptManager.runCode(ScriptManager.java:799)
	at com.inductiveautomation.factorypmi.application.binding.action.ActionAdapter.runActions(ActionAdapter.java:206)
	at com.inductiveautomation.factorypmi.application.binding.action.ActionAdapter.invoke(ActionAdapter.java:297)
	at com.inductiveautomation.factorypmi.application.binding.action.RelayInvocationHandler.invoke(RelayInvocationHandler.java:57)
	at com.sun.proxy.$Proxy40.actionPerformed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
	at java.desktop/java.awt.Component.processMouseEvent(Unknown Source)
	at java.desktop/javax.swing.JComponent.processMouseEvent(Unknown Source)
	at java.desktop/java.awt.Component.processEvent(Unknown Source)
	at java.desktop/java.awt.Container.processEvent(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)
Caused by: org.python.core.PyException: Traceback (most recent call last):
  File "<event:actionPerformed>", line 11, in <module>
java.lang.NullPointerException
	at com.inductiveautomation.ignition.common.script.builtin.DatasetUtilities$PyDataSet.pyget(DatasetUtilities.java:123)
	at org.python.core.PySequence$DefaultIndexDelegate.getItem(PySequence.java:532)
	at org.python.core.SequenceIndexDelegate.checkIdxAndFindItem(SequenceIndexDelegate.java:88)
	at org.python.core.SequenceIndexDelegate.checkIdxAndFindItem(SequenceIndexDelegate.java:70)
	at org.python.core.SequenceIndexDelegate.checkIdxAndGetItem(SequenceIndexDelegate.java:61)
	at org.python.core.PySequence.seq ___getitem__ (PySequence.java:377)
	at org.python.core.PySequence. __getitem__ (PySequence.java:373)
	at org.python.pycode._pyx6.f$0(<event:actionPerformed>:11)
	at org.python.pycode._pyx6.call_function(<event:actionPerformed>)
	at org.python.core.PyTableCode.call(PyTableCode.java:171)
	at org.python.core.PyCode.call(PyCode.java:18)
	at org.python.core.Py.runCode(Py.java:1614)
	at com.inductiveautomation.ignition.common.script.ScriptManager.runCode(ScriptManager.java:799)
	at com.inductiveautomation.factorypmi.application.binding.action.ActionAdapter.runActions(ActionAdapter.java:206)
	at com.inductiveautomation.factorypmi.application.binding.action.ActionAdapter.invoke(ActionAdapter.java:297)
	at com.inductiveautomation.factorypmi.application.binding.action.RelayInvocationHandler.invoke(RelayInvocationHandler.java:57)
	at com.sun.proxy.$Proxy40.actionPerformed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
	at java.desktop/java.awt.Component.processMouseEvent(Unknown Source)
	at java.desktop/javax.swing.JComponent.processMouseEvent(Unknown Source)
	at java.desktop/java.awt.Component.processEvent(Unknown Source)
	at java.desktop/java.awt.Container.processEvent(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)
java.lang.NullPointerException: java.lang.NullPointerException

	... 44 common frames omitted
Caused by: java.lang.NullPointerException: null
	at com.inductiveautomation.ignition.common.script.builtin.DatasetUtilities$PyDataSet.pyget(DatasetUtilities.java:123)
	at org.python.core.PySequence$DefaultIndexDelegate.getItem(PySequence.java:532)
	at org.python.core.SequenceIndexDelegate.checkIdxAndFindItem(SequenceIndexDelegate.java:88)
	at org.python.core.SequenceIndexDelegate.checkIdxAndFindItem(SequenceIndexDelegate.java:70)
	at org.python.core.SequenceIndexDelegate.checkIdxAndGetItem(SequenceIndexDelegate.java:61)
	at org.python.core.PySequence.seq ___getitem__ (PySequence.java:377)
	at org.python.core.PySequence. __getitem__ (PySequence.java:373)
	at org.python.pycode._pyx6.f$0(<event:actionPerformed>:11)
	at org.python.pycode._pyx6.call_function(<event:actionPerformed>)
	at org.python.core.PyTableCode.call(PyTableCode.java:171)
	... 42 common frames omitted

```

and the logging from the message handler is performed as expected

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/3/83ce13c0507a3a59ad29fd98e73557ead2fe032c.png)

Why do two PyDataset objects that claim to be the same type with the same python methods behave differently when trying to access data? I know that the queries are called from different scopes (client vs gateway), but I wouldn’t think the origin would matter for data of the same type.

Ignition Version: 8.1.5  
Edit: Added Database name to both runPrepQuery calls because documentation suggests it’s required in the gateway scope. It didn’t seem to make a difference.

---

<div class="post-metadata">

**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [February 17, 2022, 8:38pm UTC](https://forum.inductiveautomation.com/t/ign-5581-pydataset-over-received-from-sendrequest-behaves-differently/56278/2 "2022-02-17T20:38:57Z")

</div>

> [@zacht](#):
>
> ```auto
> Caused by: java.lang.NullPointerException: null
> at com.inductiveautomation.ignition.common.script.builtin.DatasetUtilities$PyDataSet.pyget(DatasetUtilities.java:123)
> at org.python.core.PySequence$DefaultIndexDelegate.getItem(PySequence.java:532)
> at org.python.core.SequenceIndexDelegate.checkIdxAndFindItem(SequenceIndexDelegate.java:88)
> at org.python.core.SequenceIndexDelegate.checkIdxAndFindItem(SequenceIndexDelegate.java:70)
> at org.python.core.SequenceIndexDelegate.checkIdxAndGetItem(SequenceIndexDelegate.java:61)
> at org.python.core.PySequence.seq ___getitem__ (PySequence.java:377)
> at org.python.core.PySequence. __getitem__ (PySequence.java:373)
> at org.python.pycode._pyx6.f$0(<event:actionPerformed>:11)
> at org.python.pycode._pyx6.call_function(<event:actionPerformed>)
> at org.python.core.PyTableCode.call(PyTableCode.java:171)
> ... 42 common frames omitted
> 
> ```

I'm pretty sure this is just a bug in our code. I'm going to mock up in the latest version, in case it's been incidentally fixed, but I think it's still possible.

---

<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [February 17, 2022, 8:55pm UTC](https://forum.inductiveautomation.com/t/ign-5581-pydataset-over-received-from-sendrequest-behaves-differently/56278/3 "2022-02-17T20:55:31Z")

</div>

As a work-around, convert from PyDataset to Dataset before returning from the message handler, and convert back to a PyDataset locally (if you need to).

---

<div class="post-metadata">

**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [February 17, 2022, 9:07pm UTC](https://forum.inductiveautomation.com/t/ign-5581-pydataset-over-received-from-sendrequest-behaves-differently/56278/4 "2022-02-17T21:07:32Z")

</div>

Yeah, it’s just a bug in our code. I filed a ticket to get it fixed, but the easiest solution is to wrap in a standard dataset, then convert back if required.

---

<div class="post-metadata">

**Author:** ![zacht](https://avatars.discourse-cdn.com/v4/letter/z/ea5d25/32.png) [@zacht](https://forum.inductiveautomation.com/u/zacht)\
**Post date:** [February 17, 2022, 9:20pm UTC](https://forum.inductiveautomation.com/t/ign-5581-pydataset-over-received-from-sendrequest-behaves-differently/56278/5 "2022-02-17T21:20:55Z")

</div>

> [@pturmel](#):
>
> convert from PyDataset to Dataset before returning from the message handler, and convert back to a PyDataset locally

That worked. Thank you.